Vapor deposition



li 22, 1955 R. BAKISH srm. 3,190,262

VAPOR nnrosu'xou Filed Oct. 20. 1961 ,44 v AUXILLIARY GAS l 3s 56 42 50as 22 32 54 52 24 AUXILUARY GAS COOLING e0 AUXILLIARY FEZT U rr 58 GAS5| DEcogn PgsAsLE I 78 COOLING I 80 I, 74 68 UNIT I RESIDUAL AND "KiEAUXILLIARY GAS 72 70' s4 62 F|G.l

, INVENTORS ROBERT BAKISH IWAN MARINOW BY CHARLES A. GELLAR ATTORNE Y SUnited. States Patent Ice Patented June. 22,1965

The present invention relates to the deposition of metal on sheetmaterial and, more particularly, to the deposition of metal from agaseous compound of which the metal is a component. Although the deviceof the present invention is applicable to a variety of organic andinorganic sheet materials, it is particularly useful for coating paper.In the coating of paper, many of a variety of requirements mustbe met.Thus, in the production of metal coated decorative paper, depositionmust be effected rapidly and inexpensively. And in the production ofmetal coated capacitor paper, deposition must be precisely controlled tomeet specific characteristics. In all cases, temperature, pressure andtime must be selected carefully in order to avoid scorching andoutgasing of the paper and to ensure adherence and uniformity of themetal coat. r j The primary object of the present invention is toprovide a novel device by which a metal is deposited. The heatdecomposable metal compound may be normally solid or liquid but must bevaporizable without undue decomposition. The device is characterized byan elongated convex surface in contact with which the elongated sheet istensioned and which defines, in conjunction with an associated elongatedconcave surface, a curved chamber for subjecting the elongated sheet tothe metal bearing vapor in a novel manner. The process involves thesteps of heating the elongated sheet, which specifically is composed ofpaper, and depositing on one of its faces a metal from its vapor in apredetermined sequence that results in an adherent coat of high quality.The system and process eflect the decomposition substantially at,atmospheric pressure. j H

Other objects of the present invention will in part be obvious and willin part appear hereinafter.

The invention accordingly comprises the apparatusinvolving the severalsteps and components and the relation and order of one or more suchcomponents with respect to each of the others, which are exemplified inthe following disclosure, and the scope of which will be indicated inthe appended claims. 7 T i For a fuller understanding of the nature andobjects of the present invention, reference should be had to thefollowing detailed 'descriptiom taken in connection with theaccompanying drawings, wherein:

FIGQlis an exaggerated cross-sectional diagrammatic 'view, partly brokenaway, of a device for performinga 1 and 2 involves the steps ofadvancingan elongated sheet of paper from a supply spool through acurved path to a take-up spool, the path being defined by a heatedconvex surface against which the sheet is tensioned and a cooled concavesurface which is slightly spaced from the sheet. The sheet is tensionedagainst the convex surface to prevent the back of the paper as well asthe convex surface from being affected by the deposition process. Thesheet is spaced from the concave surface and the concave surface iscooled to provide a region within which the metal bearing gas may flowin contact with the surface of the sheet to be coated and to preventdeposition from occurring on the concave surface in such a Way as toconstrict this region. The metal bearing'vapor is flowed through anentrance port into a deposition zone of the region and through an exitport from the deposition zoneQ Auxiliary gas is flowed into zones onopposite sides of the deposition zone in order to isolate the metalhearing vapor and its residue from the extremities of the region intowhich and from which the sheet advances. In this system, the metalbearing compound is an organometallic, a metal hydride, a metal carbonylor a metal halide, which may be heated in the presence of a suitableauxiliary gas, to an elevated temperature at which decomposition of thevapor and deposition of the metal occurs. 7 'It is known that usefulrates of metal deposition from such gaseous metal bearing compoundsoccur generally within the range of from 200 to l000 F. It has beenfound that paper can Withstand, without appreciable physical-chemicalchange, temperatures within the range from 1 to seconds, a typical paperbeing able to withstand without appreciable chemical change atemperature of approximately 500 F. for approximately 30 seconds. In theillustrated process, successive increments of a paper sheet are heatedand subjected to a metal bearing gas to cause metal to be reducedthereupon from a metal bearing gas. The auxiliary gas may be anactivematerial such as hydrogen or an inert material such as argon (orother noble gas) or nitrogen. The overall pressure in evaporationchamber 64 preferably ranges from .1 to 15 psi. above atmosphericpressure in order to concentrate the heat decomposable gas prior to itsentrance into decomposition zone 34. Also, this pressure prevents theoutgassed vapors from the paper from entering the decomposition zone, I

Particularly good papers for the purpose of the present inventionarecalendered papers having at least a glossy surface at which the sheetis denser than it is in its interior. v I

The metal bearing compounds to be vaporized prefen ably are selectedfrom carbonylssuch as iron carbonyl, molybdenum carbonyl, nickelcarbonyl, chromium carbonyL'tungstencarbonyl and cobalt carbonyhalkylssuch as aluminum diisobutylhydride, aluminum triisobutyl, aluminumtriethyl and molybdenum ditoluene; aryls such as chromium dibenzene,molybdenum dibenzene, vanadium' dibenzene and vanadium 'dimesitylenedi-iodide;

sandwich compounds such as bis-cyclopentadienyls of num hydride, :andtin hydride; and Q combinations -and mixtures thereof such' as alkyland. aryl carbonyls including benzene chromium tricarbonyl, phenanthrenechromium tricarbonyl, naphthalene chromium tricarbonyl,

o-xylene chromium tricarbonyl, benzene molybdenum tricarbonyl,cyclo-octadiene molybdenum tricarbonyl; bis-f cyclopentadienylchlorides, bromides and diodides'of titanium, zirconium, hafnium,vanadium, molybdenum, tungsten and tantalum, cyclopentadienyl carbonylssuch as cyclopentadienyl manganese tricarbonyl, bis-cyclopentadienylcarbonyls of molybdenum, tungsten or iron,

carbonyl'halogens such as sodium carbonyl bromide, ru-,

thenium carbonyl chloride, and organo hydride compounds such as triethylamine-aluminum hydride and trimethyl amine-aluminum hydride. 1 I Thedevice illustrated in FIGS. land 2' for performing the, process of thepresent invention is shown generally as comprising an inwardly concavewall 20 and an outwardly concave Wall 22 which define therebetween acurved.

chamber 24, the profile of which constitutes what may be termed arelatively minor segment of a closed curve. Preferably-the distancebetween the adjacent surfaces of walls 20. and 22 ranges between and574, of an inch and preferably is approximately 43 of an inch. 7 Sidewalls (notshown) complete curved chamber 24 except for its ends. Theopen ends of chamber-24am adjacent, respectively, to a supply spool 26and a take-up spool 28 for a substrate 30 to be advanced through chamber24.

Chamber 24, includes a preheat zone 32," a decomposition zone 34 and adwell zone 36. Substrate 30 advances" through preheat zone 32,decomposition zone 34 and dwell zone 36,;in sequence, while constrainedagainst wall 22 throughout its length. Wall 22 includesrsections 38, 40

and 42, which respectively incorporate separate heating 1 elements,extending throughouttheir'lengths, that are energized by a-suitableelectrical source 44.

Gaskets 46,48 and 50 respectively, partially seal zone 32 from itsexterior, zones 32 and 34 from'each other and zone 36 from its exterior.A'mixture of auxiliary and heat decomposable gas is introduced-at thejunction of zones 36 and 34 through a series of small holes in a ventcomponent 51, one hole of which is shown in FIG. 1 at 52. Additionally,auxiliary gas is introduced at the outer extremities 54 and56 of zones36 and 32. Residual and auxiliary gas is exhausted from zones 34 and 36at the junction 58 between zone 34 and zone'32, Auxiliary .gas isexhausted from zone 32 at its inner extremity 70rfor distributing heatthroughout the exterior'of vessel.

64, and a heating unit 72 for water jacket 70; In the illustration, theheat decomposable gas is supplied in liquid form as successive drops 74and is vaporized by a series'of jets 76. It willbe noted also that theconcave surface ,of zone 34 is cooled as at 78 in order to prevent.depositionthereupon and that the gas exhausted at .the

junction of zones 32 and 34 is cooled asat 80 in order to increase theexhaust elfect. In general, the temperatures generated in preheatingzone 32 and dwell'zone 36 are below the decomposition temperature of-thedecomposable gas and the temperature generated in decomposition zone 34is above the decomposition temperature; of the decomposable gas.

- EXAMPLE I A paper substrate wasadvanced throughchamber 24 of FIG. 1 at15 ft./mm'. Heating section 38 was at160 C.,

heating section 40 was at 235 C. and heating sectioni42 V was at 190 C.The spacing between the adjacent curvedsurfaces of chamber 34 was 4;inch. Water jacket 70 was at 85 C. I Thepartial vapor pressure of ironpentaearbonyl was 100 mml-lg, the totalvapor pressure within nitrogenwas introduced at slightly greater than atmospheric pressure in order toensure outward flow through. the extremities of chamber 24. The flow ofgas through decomposition chamber 34 is at the rate of 5 cu. ft./hr. acoat, 5000 A. thick, composed of 98.5% iron and 1.9%

carbon resulted. v

' EXAMPLE II The process of Example I Was repeated except that. thesubstrate was paper coated with casein. A ferromagnetic stratum wasdeposited on the casein coating.

EXAMPLE Ill The process of Example I was repeated :except that thesubstrate was Mylar. deposited.

. EXAMPLE IV iron, 24% cobalt, 14% nickel and 3% 'carbonf j EXAMPLE V apartial pressure of copper hydride and aluminum triisobutyl in'2 to 1ratio with respect to each other andin amount approximately equal to thevapor pressure of the nickel is introduced. The resulting product iscomposed of approximately 49% iron, 24% coba t, 14% nickel, 8% aluminum,3% copper and 1% carbon.

IPreferredferromagnetic strata of the above described. character areproduced in the system of EIG..1- where;

the heat decomposable gas is an iron carbonyl, preferably ironpentacarbonyl, which is liquid under usual conditions; alternatively theiron carbonyl may be iro'ndodeca carbonyl; the auxiliary gas issan inertgas such as, nitro- 0 gen; the temperature of heating section 38 rangesfrom 140180 C.; the temperature of heating section ranges from 16(5-250.C.; the partial pressure of the heat decomposable gas ranges from '75to 1 25 .mm. Hg; the auxiliary. gas issupplied in such a way as toproduce a flow through decomposition chamber 34 ranging from 1 to 10 cu.ft./hr.; and substrate 30 is advanced ata rate Accordingly, the presentinvention providesnovelsys.

tems for producing thin metallic coats 'of high quality.

Since certain changes may be made in'the foregoing de+;

scription and the accompanying drawing without depart+ ing from thescope of the invention herein involved, it

is intended that all matter discloscd'herewith be interpreted in anillustrative and not in ,a limiting sense.

5 .What is claimed is: i .An apparatus for depositing metal on anelongated sheet material, said apparatus comprising first means pro-'viding an outer concave surface and secondmeans pro- 'viding an innerconcave surface, said outer concave su r-; face and said inner concavesurfacebeing spaced, aparta distance ranging fl'Qm' /gg to inch anddefining a concave path said path providing in sequence a preheatzone, adecomposition zone and a dwell zone, means for ad-:- vancing anelongated sheetmaterial through said concave path and .tensioned againstsaid inner concave surface, means for heating said inner concave surfacesubstan- ;tially continuously throughout said decompositionzone; meansfor cooling said outer concave surface substantially continuouslythroughout said decomposition zone, '70 means defining an entrance portand ,a first, exit portatm opposite extremities. of said decompositionzone, means for directing a heatdecomposable metal bearing .gas throughsaidentrance port, said decomposition zone and said first exit port,means for directing an auxiliary gas; into said preheat zone and saiddwell zone in order to A ferromagnetic stratum was.

The process of Example IV is repeated 'except that 5 shield the outerextremities of said preheat zone and said dwell zone from said heatdecomposable gas, a first gasket at the outer extremity of said preheatzone, a second gasket at the junction between said preheat zone and saiddecomposition zone and a third gasket at the outer extremity of saiddwell zone, means defining a second exit port in said preheat zone, saidfirst exit port and said 7 second exit port being contiguously locatedon opposite sides of said second gasket, and means for exhausting saidfirst exit port and said second exit port, the profile of said concavepath being such that it constitutes a relatively minor segment of aclosed curve.

References Cited by the Examiner UNITED STATES PATENTS Pawlyk 117107.1Schladitz 117107.1 Vodonik 117-107.1 X Homer et a1 117107.1 X Marvin117-107.1 X Toulmin 1171 07.1 X

RICHARD D. NEVIUS, Primary Examiner.

